subroutine char METHOD if ( METHOD .eq. ASIS ) then set geom sele by resi atom numb $1 .a .not atom name C N O end \ group N dihe dist angle ! extend else set geom sele by resi atom numb $1 .a .not atom name C N O end \ group N dihe dist angle extend end_if image over false return set vari IRES local int resi sele by resi atom numb $1 end set vari IATOM local int atom sele resi numb IRES .a atom name CA end if ( IATOM .ge. 1 ) then set vari atom_CA inte atom sele atom name CA .a resi numb IRES end set vari atom_C inte atom sele atom name C .a resi numb IRES end set vari atom_N inte atom sele atom name N .a resi numb IRES end else set vari IATOM local int sele atom numb $1 end end_if key FIX_GEOM sele resi name IRES .a .not atom name CA N O C H end key atom_NEIG sele by bond atom numb IATOM .and. FIX_GEOM end show key atom_NEIG if ( IRESULT_4 .eq. 0 ) return if ( IRESULT_4 .eq. 1 ) then set vari atom_NEXT inte atom sele atom_NEIG end set geom dihe atom_NEXT atom_OLD1 atom_OLD2 atom_OLD3 value 180.0 - select FIX_GEOM .a cut atom_OLD2 atom_OLD1 end end_if if ( IRESULT_4 .eq. 2 ) then set vari atom_NEXT1 inte atom sele atom_NEIG end key atom_NEIG sele atom_NEIG .a .not atom numb atom_NEXT1 end set vari atom_NEXT2 inte atom sele atom_NEIG end show dihe atom_OLD1 atom_OLD2 atom_NEXT1 atom_NEXT2 if ( RESULT_0 .gt. set geom dihe atom_NEXT atom_OLD1 atom_OLD2 atom_OLD3 value 180.0 - select FIX_GEOM .a cut atom_OLD2 atom_OLD1 end end_if if ( IRESULT_4 .eq. 3 ) then end_if if ( IRESULT_4 .ge. 4 ) then end_if return defin clas sele segm name SEGMENTS end by root CA